Broadloom carpet is conventionally manufactured by tufting the face yarns into a woven or nonwoven primary backing. Conventional woven primary backing may have a bowed or skewed pick line due to the typical construction of the fabric. A bowed pick line is one where the ends of a fill yarn are at basically the same distance along the length of the fabric, but the fill yarn between the edges gains or loses in distance along the length (bends or curves). Bow is measured by drawing a straight line between the two ends of a fill yarn and measuring the greatest distance from this straight line to the fill yarn in the body of the fabric. A skewed pick line is one where the fill yarn is basically straight, but one end of the fill yarn gains or loses along the length of the fabric. Skew is measured by drawing a straight line perpendicular to the fabric edge from one end of the filling and measuring the distance of the opposite end of the fill yarn from the perpendicular line.
After the face yarns have been tufted into the primary backing, there is a face side of the carpet that will be visible after installation and there is a backside of the primary backing which is covered by the backstitch or the exposed crossovers of the face yarn after insertion through the backing. The backstitch is secured by application of an adhesive and a secondary backing fabric. The adhesive acts to bind the backstitch while the secondary backing contains this adhesive and acts to further stabilize the structure of the carpet. The most popular adhesives currently in use are different types of latex commonly styrene butadiene latex.
It is critical that pattern broadloom carpet have straight pattern lines perpendicular to the edge for installation purposes. If the pattern lines are not straight at the time the carpet is coated and the secondary backing is applied, the bow or skew will be set into the carpet. Bow and skew may be due to bowed or skewed primary backing and/or tension variations in the carpet manufacturing processes. Small degrees of bow and skew may be compensated for during the carpet manufacturing processes or during installation through stretching techniques.
The foregoing problems are often the result of tucking of the severed weft yarns (picks) on opposing sides of the primary fabric. Tucking is necessary to prevent unwarranted raveling of the fabric, which would otherwise occur with subsequent handling during manufacture of the carpet. Tucking of the weft ends results in a build-up of the thickness in the selvages (edges) of the fabric which accumulates in a roll of fabric to create a dog-bone effect at each edge.
The resulting dimensional changes in the fabric can alter the desired tufting of the face yarns in a pre-determined pattern and as a result, during installation of the carpet, the alignment of patterns in adjacent rolls of the carpet can be off sufficiently that it cannot be corrected by stretching. Such problems are particularly notable in large rooms such as banquet halls, meeting rooms, gambling casinos and the like, which must be closed for re-carpeting. In many instances carpet installers arrive with hundreds of square yards of carpet and when pattern alignment are experienced, it may not be possible to complete the job until different rolls can be delivered, if indeed, they will fare better. Given the loss of revenue for just one evening""s activities, and the fact that the work must still be done at a later date, and the need for uniform carpet can be appreciated.
One solution to the selvage problem is to untuck every other pick line so that the selvage area does not increase in thickness to a degree sufficient to result in build-up. U.S. Pat. No. 3,457,966 describes an apparatus and method for forming a tucked in selvage characterized in that certain weft yarns are periodically not tucked, so as to provide a woven fabric having reduced thickness selvages.
Typical nonwoven primary backing is constructed in such a manner that there is no bow or skew possible due to the orientation of the fibers. Although this orientation eliminates bow and skew due to the primary, the appearance of the carpet is muted because the nonwoven fabric does not heal itself and close back around the face yarn as with the woven fabric. Tufting efficiencies with nonwoven primary fabrics are typically reported to be lower than those of woven primary backings.
While attempts have been made heretofore to manufacture woven fabrics with reduced selvages, the art has not provided a facile means or device by which to do so. Nor, has the art necessarily provided a woven fabric or roll of fabric that can be utilized in the manufacture of broadloom carpet which is consistently uniform in dimension.
It is therefore, an object of the present invention to provide a novel woven fabric having a reduced selvage area.
It is another object of the present invention to provide a novel woven fabric having intermittently spaced contrasting fill lines for diagnostic purposes.
It is another object of the present invention to provide a roll of woven fabric having a reduced selvage area such that the diameter of the roll is essentially the same at the ends as it is across the center of the roll.
It is yet another object to provide a woven fabric, according to the present invention for use as a primary backing in the manufacture of broadloom carpet.
It is yet another object to provide a woven fabric, according to the present invention, having reduced bow and skew.
It is yet another object to provide a woven fabric, according to the present invention, having a tucked-untucked selvage.
It is yet another object to provide a woven fabric, according to the present invention, having a tucked-untucked selvage providing greater tensile strength of fabrics utilizing a leno latch weave to control the selvage.
It is yet another object of the present invention to provide an assembly for use on a weaving loom to provide a woven fabric having a tucked-untucked selvage.
It is still another object to provide a method for the operation of a weaving loom to provide a woven fabric having a tucked-untucked selvage.
At least one or more of the foregoing objects, together with the advantages thereof over the known art pertaining to woven primary backing fabrics and related apparatus and methods for the manufacture thereof, which shall become apparent from the specification which follows, are accomplished by the invention as hereinafter described and claimed
In general the present invention provides a roll of woven fabric having a length greater than the diameter thereof wherein the diameter is substantially the same across the length of the roll.
The present invention also includes an assembly operable with the tucking units of the picking and receiving ends of a weaving loom for producing woven fabrics comprising plate means attached to the loom; main drive block means connected to a harness of the loom; operating rod means, having first and second ends and attached to the main drive block means at the first end and pivotally mounted to an upper surface of the plate means at the second end; lifter means connected to the operating rod means, proximal to the second end, for lifting the weft end gripper of the loom; and means for selectively engaging the weft end gripper, operatively associated with the operating rod means, whereby the weft end gripper positions consecutive pick lines in an alternating fashion, allowing every other one to be tucked into the selvage of the fabric, while adjacent pick lines are untucked.
The present invention also includes a method for producing woven fabrics having a tucked-untucked selvage comprising providing an assembly at the picking and receiving ends of a weaving loom, operable with the weft end grippers of the loom; attaching the assembly to a harness of the weaving loom; and operating the assembly so that the weft end grippers move every other weft yarn out of reach of the tucking needles of the loom.
The present invention also includes a method for producing woven fabrics having a tucked-untucked selvage on a weaving loom, providing selvage edge grippers and tucking needles, comprising moving the selvage gripper the forward to capture a weft yarn end; opening and closing the clamp of the selvage gripper onto the weft yarn end; catching the weft yarn end with the tucking needle and tucking it into the selvage; moving the selvage gripper forward to capture the next weft yarn end; opening and closing the clamp of the selvage gripper onto the next weft yarn end; retracting the selvage gripper and the next weft yarn end into the shed while raising the selvage gripper out of the path of the tucking needle, causing the needle to miss the yarn end; releasing the untucked yarn end; and thereafter repeating the foregoing steps in alternating fashion to produce a woven fabric having a tucked-untucked selvage.